Technical Field
The present disclosure relates to a semiconductor device.
Related Art
For example, in an analog-digital (AD) converter, a digital-analog (DA) converter, and the like, a resistance voltage dividing circuit including a serial resistance section in which plural resistance elements are connected in series, and a constant-current source which is connected to each of one end and the other end of the serial resistance section, is used (for example, see Japanese Patent Application Laid-Open (JP-A) No. 2003-078415).
FIG. 8 illustrates an example of a resistance voltage dividing circuit 100. The resistance voltage dividing circuit 100 includes a serial resistance section 110 in which resistance elements R1 to R12 are connected in series, and constant-current sources I1 and I2. The constant-current source I1 is a constant-current source of a so-called discharge type which discharges a bias current Ibias1. The constant-current source I1 supplies a power-supply voltage VCC from one end thereof, and the other end thereof is connected to one end of the serial resistance section 110. Further, the constant-current source I2 is a constant-current source of a so-called sink type which sinks a bias current Ibias2, and has one end being connected to the other end of the serial resistance section 110 and the other end being grounded. Further, a voltage Vin is input to a connection point between the resistance element R6 and the resistance element R7.
In the resistance voltage dividing circuit 100 configured in this manner, a divided voltage is output from each connection point among the resistance elements R1 to R12. In a case in which each resistance value of the resistance elements R1 to R12 is set to r, for example, a voltage of Vin+Ibias1×r×n (n=5 to 1) is output from each connection point among the resistance element R1 to R6. Further, a voltage of Vin−Ibias2×r×n (n=1 to 5) is output from each connection point among the resistance element R7 to R12. Further, the voltage Vin is output from the connection point between the resistance element R6 and the resistance element R7.
In a semiconductor device including the resistance voltage dividing circuit 100 described above, when operating the device, it is important for the bias current Ibias1 discharged by the constant-current source I1 and the bias current Ibias2 sunk by the constant-current source I2 to be equal.
For example, in a case in which the bias current Ibias1 and the bias current Ibias2 are different, current flows out to an input terminal side to which the voltage Yin is input, and thus, is such case, the device may not properly operate.
Further, for example, in a case in which the bias current Ibias1 and the bias current Ibias2 are different, a degree of rise in potential from the voltage Yin in each connection point among the resistance element R1 to R6 and a degree of drop in potential from the voltage Yin in each connection point among the resistance element R7 to the resistance element R12 becomes different from each other, and thus, is such case, the device may not properly operate.
However, in JP-A No. 2003-078415 described above, there is no description regarding a layout of the elements configuring the resistance voltage dividing circuit 100 that allows the bias current Ibias1 and the bias current Ibias2 to be equal.